There are known in the prior art, merchandising machines which dispense a wide variety of articles having different shapes and sizes and varying shelf lives, such for example as sandwiches, food platters, milk and desserts. These machines are of two general types.
In one type of general merchandiser, which operates in the "first-in, first-out" mode, individual drives are provided for each level. Selecting means energizes the drives so as to step the selected level through one step while leaving the unselected levels at rest.
In a second type of general merchandiser, a carrier having a plurality of compartment levels associated with respective normally locked access doors is mounted for movement as a unit and is driven in response to actuation of a transport button selectively to position any compartment of the carrier behind its access door. This mode of operation is known as the "shopper" mode. A merchandiser of this type is disclosed in the application of Merrill Krakauer, Ser. No. 146,313, filed May 5, 1980, for All-Purpose Merchandiser, now U.S. Pat. No. 4,317,604 issued Mar. 2, 1982.
Both of the machines described above suffer from a number of disadvantages. While the "shopper" machines provide excellent merchandising appeal, the lack of control over the order in which products are sold results in a high order of "throw aways", as a result of spoilage. Merchandisers of the type described above which operate in a "first-in, first-out" mode, in which the customer is required to purchase the oldest product in the selected level, provide better control of loss of product. However, they require individual drives for the respective levels. Moreover, they do not afford merchandising appeal, owing to the limited choice offered to the customer.
It is clear that the "shopper" type merchandisers are desirable for vending a product with a relatively long shelf life and several different flavors or varieties, such for example as yogurt, while the "first-in, first-out" type merchandisers are desirable for vending products with a relatively short shelf life and fewer, if any, flavors or varieties, such for example as whole milk. A merchandiser, the operation of which is limited to one of the two modes, cannot efficiently dispense both long shelf life articles or articls of wide variety as well as short shelf life articles or articles of limited or no variety.